This invention relates in general to water pressure controlled indexing means for irrigation sprinkler systems employing a plurality of pilot valves for operating individual sprinklers, or group of sprinklers in the system, and more specifically to an improvement in such indexing means for operating each of the indexing means to a predetermined initial indexing position in response to a predetermined operation of system pressures in order to assure the correct sequential operation of each indexing means to attain a reliable and predictable operation of the sprinklers or group of sprinklers.
It is now common to provide a plurality of sprinklers or group of sprinklers whose water supply comes from a common source, frequently through common conduits with the individual sprinklers, or group of sprinklers, being selectively operated by associated pilot valves. It may be desirable to operate any individual sprinkler, or group sprinklers, only one to one and a half hours per day and it is highly desirable that a plurality of such sprinklers, or groups, be serviced from a single water conduit in order to save installation expenses which might otherwise be incurred if each sprinkler were required to have its own water supply conduit running over any substantial length of ground from a water source. Various water pressure operated systems have been employed heretofore wherein individual pilot valves are provided to operate individual sprinklers, or group of sprinklers, with the pilot valves being indexed in response to variations in system pressure. However, I have found that in these prior water pressure operating indexing systems, that it is still possible for the individual indexing means to malfunction intermittently and either fail to operate, or fail to operate in the predetermined sequence intended. It is therefore the primary object of the present invention to disclose and provide an improved water pressure controlled indexing means for irrigation sprinkler systems wherein the reliability of operation of the indexing means is improved so that a predetermined sequence of operation of a plurality of pilot valves in a sprinkler system operated by a plurality of water pressure controlled indexing means can be assured. It is a further object of the present invention to disclose and provide such an improved indexing means which will be less complicated in its construction and mode of operation then those provided heretofore, which will provide a visual indication that the system is operating correctly and will provide for manual override of the automatically operating indexing means when desired.